Study of charge dynamics in transparent single-walled carbon nanotube films

摘要

We report the transmission over a wide frequency range (far infrared -visible) of pristine and hole-doped, free-standing carbon nanotube films attemperatures between 50 K and 300 K. Optical constants are estimated byKramers-Kronig analysis of transmittance. We see evidence in the far infraredfor a gap below 10 meV. Hole doping causes a shift of spectral weight from thefirst interband transition into the far infrared. Temperature dependence inboth the doped and undoped samples is restricted to the far-infrared region.